Selector switch brush unit assembly



Dec. 11, 1951 G. DEAKIN SELECTOR SWITCH BRUSH UNIT ASSEMBLY 2 SHEETS-SHEET 1 Original Filed Sept. 14, 1946 INVENTOR. G ERALD DEAKIN A TTORNE Y.

G. DEAKIN 2,577,742

Dec. 11, 1951 SELECTOR SWITCH BRUSH UNIT ASSEMBLY 2 SHEETS-SHEET 2 Original Filed Sept. 14, 1946 FIGJO.

F IG.8.

Patented Dec. 11, 1951 UNITED STATES PATENT OFFICE Gerald Dea'kin, New York, N. Y., assignor to International- Standard Electric Corporation, New York, N. Y., vacorporation of Delaware Original applicatiouseptember 14, 1946, Serial No. 697,148. Divided and this application July 9, 1948, Serial No. 37,753

' .12- Claims. (01. 2004-166) 1 This invention relates to new and useful improvements in brush units suitable for assembly into brush sets of selector switches. The present is a division of my application Serial No. 697,148, filed September 14, 1946. r

The object of the present invention is theprovision of a brush unit simple to make and one that can be readily assembled into the selector structure.

With this objectin view I provide the construction which will be clear from the following description, claims and the drawings illustrating several embodiments of the invention.

In these drawings:

Fig. 1 is a view, on an enlarged scale, of one of several brush units entering into a complete brush assembly;

Fig. 12 is a perspective view showing the novel carriage mounts.

As shown in Figs. 1 to 4A, each brush unit is composed of two distinct complementary. segments 32, 33 of suitably tempered spring material as, for example, Phosphor bronze, and each complementary segment is centrally depressed and laterally extended, forming tabs 36, 31, on one segment in juxtaposed relationship to the corresponding tabs 38, 39,0f the complementary segment. Backing strips 4|, 42 cover these tabs, and are in turn retained in the non-conducting brush holder 43 with which each brush unit is individually provided; the novel retaining means consisting of hairpin-shaped clamping springs 44 covering the end portions of the backing strips 4|, 42 and also pressing resiliently against the sides of ribs 46 (seeFig. 4A) integrally formed on adjacent parts of each brush holder 43. Thus each brush unit is effectively retained and positioned in its individual insulating holder. The several units comprising the complete brush assembly are in turn retained in assembled relationship.

The central depressions formed in the brush complements, as above noted, have the advantage of allowing wider movement of the working end portions of the brushes, without introducing any substantial variation in brush tension. Addition- 2 ally, the brush complements are preferably edge turned along their sloping edges, as indicated at 5| and 52 in Figs. 1 and 4, as this stiffening treatment protects the parts against bowing or warping, and insures maintenance of firm contact pres sure upon the stationary circuit parts engaged by the brush ends. The latter are preferably silvercoated along the engaging surfaces, to the degree indicated by the slanting dash lines 53, 54 in Fig. 1; this coating material being preferalby applied as an inlay. The brush construction and contour are such as to facilitate production of the brush elements on a multi-slide stamping machine operating upon a continuous strip of metal of selected width, to effect blanking, forming, and tensioning of the brush elements in one continuous series of operations;

The tensioning of the brush elements is such as urge their tips 56 firmly against opposite sides of the'particular bus bar or feederstrip 3| of a selector engaged thereby, and to urge their tips 57 firmly against opposite sides of the terminal contact pins 35 of the selector terminal bank engaged thereby in succession as the brush carriage travt erses its prescribed path of travel.

To mount a set of brushes in a carriagerectangularblocks 6|, 62 (Fig. 12) are provided at opposite sides of brush carriage chassis 27, the said blocks being of natural or synthetic rubbery material (neoprene being an example thereof) and of a length and width suitable for their proper registry, first with the trunnions 63 (Figs. 1, 9, l0 and 11) projecting from opposite ends of each brush hold-' er-the blocks 6|, 62 being apertured, as shown at 64, to receive said trunnionsand secondly, with the space between flaps 28, 29 on the carriage chassis. Each block is secured to the chassis by a spring clamp 66 having a lip 61 to engage a flange 68 of the chassis, and an opposite lip 69 extending around an edge of the chassis. The effectiveness of this arrangement as a vibrationdamping support for the brush assembly, as well as its simplicity, can readily be understood from this illustration and description of this presently preferred embodiment.

The brushes are mounted in the carriage 2'! with the contacts 56 up to engage the bus bars 3| extending under the top of 27.

Figs. 5 to 8 show a modified type of brush unit utilizing the same form of two-part brush, but a different form of backing, spacing and clamping means therefor, consisting of backing strips MI and M2, spacers I43, and clamping eyelets I44 to clamp the spring tabs and backing strips in assembled relationship; the strips MI and I42 having lateral extensions I5l, I52 to grip and hold said spacers I43 to the assembly, and 1ongitudinal extensions I63 to fit into the apertures 64 (Fig. 12) of the cushioning blocks 61, 62 as do the corresponding extensions 63 of insulator 43 of Figs; 9- to 11. It will be noted that the parts I, 2,143, H4 and IE3 of Figs. 5 to 8 are substantially comparable in functions to parts 4|, 42, 43, 44 and 63 respectively, of Figs. 1 to 4. Ac-' cordingly, if desired, the assembly of Figs. 5 to 8 may be substituted for that of Figs. 1 to 4.

In comparable manner, other substitutions and rearrangements of parts, as well as. modifications in the mode of operation, may be resorted to without deviatin from the principles of the invention, as herein indicated.

What is claimed is: r

1. In a brush unit, a plurality of complementary brush segments having centrally bent portions contacting each other, laterally extending tabs formed by said portions and: lying. one-v against another, a pair of insulated backing strips; lying against the outer surfaces of: said.

tabs,.said. backing strips having mounting extensions extending therefrom and formed integraltherewith, and means including members engageable with said tabs and backing. strips. for holding; said brush segments in predetermined relationship;

2. In a" brush unit for selector switches hav- 4; The brush unit, according to claim 3, and in which the trunnions are integral with the in-- sulating brush holder.

5:. The-brush unit, according to claim 2, includ-- ing. mounting trunnions' extending; laterally from the, unit, and in which the: trunnions are inte gral with the bars.

6-. The brushunit, according; to claim 2;;an'd' in which the insulating brush holder is provided with an opening. within which lie the central wiper portions.

7. The brush unit, according to claim 6, and in which the central portions of the wipers have extended lateral tabs and the bars are within the opening in the brush holder and are riveted to the central portions of the wipers.

8. The brush unit, accordingtoclaim 2, in which the insulating brush holder hasan opening within which lie the central wiper portions, and means for clamping the bars to the holder.

9. The, brush unit, according to claim 2, and in which the brush holder is a strip of insulating material below saidbars, which is straddled by the wipers, and the bars are of metal and have lateral. extensions thereon connecting them with the holders- 10; In a brush unit for selector switches havbrush holder having a central opening, mounting trur i'nions laterally projecting from said holder, a brush wiper on each side of said holder, each wiper'h'aving a-first, and a second restricted contact. making end projectin beyond the holder and formed to engage a feeder bar and the terminal pins, respectively; each wiper fu'rth'er having a central portion bent to contact within the opening. of the holder with the corresponding portion of the other-wiper, lateral tabs projecting from each central portionwithin said opening,

triangular segments joining the ends of each wiper with the central portion, the triangular GERALD DEAKIN.

REFERENCES CITED 'lhe following references are of record in the file of this patent-5 UNITEDv STATES PATENTS.

Number Name Date 687,669 Thomas Nov. 26, 1901 906,738 Peterson Dec; 15, 1908 1,555,000 Gibbons Sept. 29', I925 

